Device for supplying superheated water

ABSTRACT

A device ( 1 ) for supplying superheated water, comprising a container ( 3 ) for containing water, and a heating element ( 5 ) for heating water in the container to a superheated state. During use the water in the container is superheated, by the heating element typically 120 to 140° C. The pressure in the container is suppressing the evaporation of the water If this superheated water is released from the container via a water outlet ( 7 ) for letting out superheated water, it evaporates due to decrease of pressure when leaving the container As a result the increased. The invention is further related to domestic appliance comprising a device for supplying superheated water

FIELD OF THE INVENTION

The invention is related to a device for supplying superheated water,comprising a container for containing water, and a heating element forheating water in the container to a superheated state. The invention isfurther related to a domestic appliance comprising a device forsupplying superheated water.

DESCRIPTION OF THE PRIOR ART

A device for supplying superheated water is known in practice. A heatingelement provides heat to water present in a container, such that thewater is superheated, typically 120 to 140° C. Usually while generatingsuperheated water the container is closed; this means that the pressurein the container is suppressing the evaporation of the water. Inpractice such a device is also referred to as a pressure cooker.

The device for supplying superheated water comprises the heating elementhaving a power P1 and the container for containing water. Duringoperation the heating element heats the water in the container therebygenerating superheated water and steam. Due to gravity water is presentin what is usually called the lower part of the container and steam ispresent in the upper part of the container. In known devices an openingis present in the upper part for letting out steam. The opening isusually provided with an electro valve to control the amount of steamthat is let out of the container. The amount of steam available in thecontainer depends on the power P1. The higher the power P1, the moresteam available in the container and therefore the higher the steamrate. In domestic appliances however, the power PI is limited to thepower available from a power/wall socket. As a result the amount ofsteam available in the container is limited to a certain maximumcorresponding to P1.

SUMMARY OF THE INVENTION

It is an object of the invention to improve the device of the kindmentioned in the opening paragraph in order to increase the amount ofsteam generated by the device.

This object is achieved by a device for supplying superheated water,comprising a water outlet for letting out superheated water. The deviceaccording to the invention is defined in claim 1.

Superheating (sometimes referred to as boiling retardation, boilingdelay, or defervescence) is the phenomenon in which a liquid is heatedto a temperature higher than its standard boiling point, withoutactually boiling. The term superheated water refers to liquid waterunder pressure between 100° C. and its critical temperature, 374° C.During use the water in the container is superheated, by the heatingelement typically to 120-140° C. The pressure in the container issuppressing the evaporation of the water. If this superheated water isreleased from the container via the water outlet for letting outsuperheated water, it evaporates due to decrease of pressure whenleaving the container. In practice the water outlet is at leastpartially below the water level during use. Experiments have shown thatusing the device according to claim 1 leads to a larger amount of steamthan usually is obtained with steam generated in the container usingpower PI and released from the container via the opening in the upperpart of the container.

This way the object of the invention is achieved.

Steam in this paper may be dry steam or wet steam depending on theamount of water present.

In a preferred embodiment of the device according to the invention thecontainer is provided with a water zone and a steam zone, the wateroutlet being located at least partially in the water zone.

The water zone is the zone in the container where during use water ispresent, the steam zone is the zone in the container where during usesteam is present.

The water outlet may be a water discharge opening in a wall of thecontainer.

During use the water outlet is in contact with water present in thecontainer.

The water outlet opening may be present at the—during use—bottom of thecontainer. As water will flow to the lowest point this is an easy way toensure that water in the container is present at the water outlet and,if at superheated temperature, available for generating steam.

Alternatively the water outlet may be present as an opening in a sidewall of the container, preferably near the bottom. During use the wateroutlet is—at least partly—below the water surface.

In another alternative the device comprises a water transfer path, suchas a hose, a pipe or a tube. The water transfer path connects an openingin the wall of the container, a so-called wall opening-with waterpresent in the water zone. In this alternative the water outlet is anopening in the pipe or tube, whereby the water outlet is located in thewater zone. Practically it may be that one end of the tube is hanging inthe water, while the other end is connected to the wall opening. Such aset up may be practical in case, for instance for construction purposes,the wall opening is located close to the top or in the top of thecontainer, while the water is at a level such that it is not in contactwith the wall opening.

In an embodiment according to the invention the water outlet isconnected to an evaporation space for evaporating superheated water. Theevaporation space may for example be an evaporation chamber or a pipe.The pipe may have an increased radius to facilitate evaporation of thesuperheated water.

In an embodiment of the device according to the invention, the devicecomprises a water inlet for letting water into the container, the waterinlet being located in the steam zone. The steam is the zone is in theupper or higher part of the container during use. If the water inlet islocated in the steam zone water upon entrance of the container waterwill fall under the force of gravity into the water zone. This way theamount of water in the container may easily be replenished.

In an embodiment of the device according to the invention, the wateroutlet comprises a valve having an open and a closed position. In theopen position superheated water will be let out for generating steam,after sufficient superheated water has been let out the valve will beclosed. Usually the valve will be controlled by a controller forcontrolling the position of the valve in dependence of user input. Forinstance if the user presses a steam-shot trigger the valve is set tothe open position generating a shot of steam. Alternatively the user maygive a steam-flow trigger that results in a prolonged opening of thevalve and thus of a prolonged expelling superheated water.

If the water outlet is partly above the water surface, steam generatedinside the container will escape together with the superheated water ifthe valve is in its open position. If the water outlet is completelybelow the water surface, a larger amount of water will be expelled fromthe container if the valve is opened. As a result a larger amount ofsteam is generated from evaporating superheated water if the wateroutlet is complete below the water surface during use.

The container may have a steam outlet opening located in the steam zone.Such a steam outlet may be used for letting out steam generated insidethe container. This is a usual configuration in known boilers or steamgenerators. This way a regular flow of steam is obtained. The steamgenerated from evaporating superheated water may be used to give anadditional shot of steam on top of the regular flow of steam.

In a preferred embodiment of the device according to the invention, thedevice further comprises a steam outlet located in the steam zone, thewater outlet being in communication with a first transfer path and thesteam outlet being in communication with a second transfer path.

The water outlet for generating steam form superheated water isconnected to the first transfer path, such as a first hose or a firstpipe.

An electro valve, further also called first electro valve, may besituated at the outside of the container at the location of the wateroutlet between the water outlet and the transfer path. Such electrovalve is used for controlling the release of superheated water from thecontainer.

The steam outlet is located in the steam zone of the container and isarranged for letting out the regular flow of steam which is present inthe container. A second electro valve may be provided at the steamoutlet for controlling the release of steam from the container. Thesteam outlet is connected to the second transfer path, such as a secondhose or a second pipe.

This way each transfer path may be used to provide steam at a differentregion during use. For instance in combination with an iron having asoleplate, each transfer path may be used to provide steam at adifferent region in the sole plate. This provides flexibility in thedesign. For instance steam generated from superheated water may, via thefirst transfer path, be transferred to a front zone located at the—socalled—tip of the iron. The steam obtained from the steam zone in thecontainer may, via the second transfer path, be transferred to a backzone in the sole plate located closer to the—so called—heel of the iron.

In another embodiment the first and second transfer path are joined to amutual transfer path. By joining the first and second transfer path to amutual steam transfer path the regular steam and steam generated fromevaporating superheated water outside the container may be combined toone stream of steam or may be used alternating. This way operationalflexibility of the device according to the invention is obtained.

The domestic appliance according to the invention comprises the deviceaccording to the invention.

The steam generated by evaporation of superheated water outside thecontainer may be used for instance to iron a piece of garment, to steamcurtains, to steam milk and generate foamed milk, to make coffee such asespresso or to clean at least a part of a surface to remove for instancecalc or dirt or a combination thereof.

In a practical application the device for supplying superheated watermay be part of a boiler ironing system.

The boiler ironing system comprises a steam iron and the device forsupplying superheated water.

In an embodiment of the domestic appliance, the domestic appliance is agarment care system such as a so-called boiler ironing system. Theboiler ironing system comprises the device according to the inventionand further comprises an steam iron having a sole plate opening forletting out steam, the system having a communication unit fortransporting an output of superheated water from the water outlet to thesoleplate opening. In practice the output of superheated water close tothe water outlet will comprise steam and some water. Further along thecommunication unit, more water may evaporate and the ratio steam/watermay increase.

The device for supplying superheated water comprises the heating elementhaving the power P1 and the container for containing water. Duringoperation the heating element heats the water in the container therebygenerating steam. The container is usually provided with an electrovalve through which steam can be transferred to the iron. The steam ironcomprises a sole plate with a sole plate surface, a steam chamber and asecond heating element having a power P2 for heating the steam chamberand the sole plate surface. The sole plate has at least one sole plateopening located in the sole plate surface for letting out steam to apiece of garment. Usually, a hose is provided between the electro valveand the steam chamber through which hose steam can be transported to theiron.

In practice if the electro valve is triggered, it opens and the outputof super heated water, which may also be referred to as yield of superheated water, travels from the container, also referred to as boiler, tothe iron. Finally, steam leaves the iron through the sole plate openingsin the sole plate of the iron.

The amount of steam available for ironing i.e. leaving the iron per unittime is called the steam rate. The steam rate depends on the amount ofsteam available in the boiler.

The higher the power PI, the higher the steam rate.

The heating element for heating the soleplate and the steam chamber inthe iron needs a certain minimum of power: P2(min) for converting waterdroplets into steam and for heating the soleplate. Because the totalpower of the system (Ptotal=P1+P2) is limited to the power availablefrom a power source, particularly a power/wall socket, P1 is limited toa certain maximum (P1(max)=Ptotal−P2(min)). As a result the amount ofsteam available in the boiler is limited to a certain maximumcorresponding to P1.

The device according to the inventions increases the amount of steamavailable while keeping P2 at least at P2(min). By applying the deviceaccording to the invention an increased amount of steam is available forironing.

The device may be used in a domestic appliance or for instance in asteam cleaner.

The steam cleaner may be used to clean a surface.

The device may be used to clean a surface in the domestic appliance,such as to remove dirt and/or calc from at least a part of the surfaceof inside of the iron, such as at least a part of the steam chamberand/or the steam channels.

In an embodiment of the domestic appliance, the domestic appliance is agarment care system further comprising a steamer having a steameropening for letting out steam, the system having a communication unitfor transporting an output of superheated water from the water outlet tothe steamer opening.

Alternatively the domestic appliance may be an espresso apparatus or acoffeemaker or the like.

The invention further relates to a method for generating steam using adevice for supplying superheated water, comprising

-   a container for containing water,-   a heating element for heating water in the container to a    superheated state, and-   a water outlet for letting out superheated water,

wherein the water outlet comprises a valve having an open and a closedposition,

the method comprising the steps of:

providing a water level in the container such that the water outlet isat least partially below the water level and

heating water to a superheated state, after that

using the valve in the open position.

The method for generating steam according to the invention may be usedfor generating for instance a flow of steam or a shot of steam. The shotof steam may be generated by applying the above mentioned steps whereinthe valve is used in the open position for a short period of time,typically in a range of 0.1-3 seconds. In practice the shot of steam maybe used to remove wrinkles from a heavily wrinkled piece of garment, forinstance during ironing.

The method may be executed using the boiler ironing system or thegarment care system according to the invention.

In practice the container, also referred to as boiler, is usually usedin combination with a water tank, which is separately arranged from theboiler, and a pump for pumping water from the water reservoir to thecontainer. The boiler comprises the heating plate connected to theheating element. The electro valve is arranged to open to let steam bereleased via the steam delivery hose. The boiler usually furthercomprises a pressure sensor to measure the pressure inside the boiler, awater level sensor and a safety valve that opens if the pressure insidethe boiler is too high in relation to a reference value. To fill thecontainer, water is pumped by a water pump from the water tank to theboiler. A de-airing valve may be present to let air out of the water.The water level sensor activates the water pump to pump water and thusset the water level inside the boiler.

There are different ways of determining the water level inside theboiler, examples are:

Measure the temperature at a wall of the container, this may be doneelectronically or using a bi-metal set at a certain temperature, andprovide a threshold temperature at which new water is pumped into theboiler.

Provide an electrode inside the container from the top down to justabove the bottom, without touching the bottom. The electrode determinesthe water level and gives a signal to a water level controller. Thewater level controller compares the signal to a set value correspondingto the location of the water outlet. If the water level is lowered to avalue close to the location of the water outlet the boiler is filledwith new water.

Before the valve is opened to generate steam from superheated water, twoconditions have to be fulfilled: the water level has to be high enough,this means the water outlet has to be at least partially below the waterlevel and the water has to be in the superheated state. If these twoconditions are fulfilled and the valve connected to the water outlet isopened, the superheated water will be let out to evaporate and thussteam is obtained.

The invention also relates to any possible combination of features orsubject matter as claimed in the claims.

The invention will now be exemplarily described with reference to theaccompanying drawings. In principle all aspects can be combined.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 schematically depicts a first embodiment of the device accordingto the invention.

FIG. 2 schematically depicts a second embodiment of the device accordingto the invention.

FIG. 3 schematically depicts a third embodiment of the device accordingto the invention.

FIG. 4 schematically depicts an embodiment of the domestic applianceaccording to the invention.

DETAILED DESCRIPTION OF DRAWINGS

In FIG. 1 a first embodiment of the device 1 according to the inventionis schematically depicted. The device 1 comprises a container 3 forcontaining water having a heating plate 6 comprising a heating element(5), and a water outlet 7 for letting out superheated water. An electrovalve 9 having an open and a closed position, is connected to the wateroutlet 7. The water outlet 7 is located at the bottom of the container.The container 3 further has a water inlet 11 to facilitate filling thecontainer with water. The inlet 11 is provided with a pump 13, forpumping water into the container. The container 3 depicted in FIG. 1comprises water. The part of the container 3 that comprises water iscalled a water zone 17. The zone above the water level 16 is referred toas a steam zone 15. The water outlet 7 is located in the water zone 17,i.e. it is located at least partially below the water surface 16.

The heating element 5 heats the water in the container to a superheatedstate. During heating the electro valve. 9 is in closed position. Afterthe water reaches its superheated state, the electro valve 9 may betriggered to its open position and as a result superheated water will belet out of the container 3 via the water outlet 7. The water will atleast partially expand at an evaporation space outside the container 3,a suitable location for the evaporation space is schematically indicatedby nr 4.

The evaporation space may for example be an evaporation chamber or awidened pipe to facilitate evaporation of the superheated water.

In FIG. 2 a second embodiment of the device 100 according to theinvention is schematically depicted. The device 100 comprises acontainer 103 for containing water having a heating plate 106 comprisinga heating element 105 and a water outlet 107 for letting out superheatedwater. An electro valve 109 having an open and a closed position, isconnected to the water outlet 107. The container depicted in FIG. 2comprises water. The part of the container that comprises water iscalled a water zone 117. The zone above the water level is referred toas a steam zone 115. A water transfer path 108, such as a hose, a pipeor a tube, connects a sidewall opening 102 in the container 103 to waterpresent in the water zone 117. This way an end of the water transferpath 108 forms the water outlet opening 107.

The heating element 105 heats the water in the container to asuperheated state. During heating the container is closed, the electrovalve 109 is in its closed position. After the water reaches itssuperheated state, the electro valve 109 may be triggered to its openposition and as a result superheated water will be let out of thecontainer via the water outlet. The water will expand at an evaporationspace outside the container, a suitable location for the evaporationspace is schematically indicated by nr 104. The evaporation space 104may for example be an evaporation chamber, a pipe or a tube. In thisset-up water leaves the container 103 at the sidewall opening 102located in the steam zone 115 of the container. The sidewall opening inthis embodiment is located away from the heating element, which islocated at the bottom. The skilled person may choose alternativearrangements.

The container 103 may also comprise a fill opening for filling and/orrefilling the container with water.

In FIG. 3 the third embodiment of the device 200 according to theinvention is schematically depicted. The device 200 comprises acontainer 203 for containing water having a heating element 205connected to a heating plate 206, and a water outlet 207 for letting outsuperheated water. A first electro valve 209 having an open and a closedposition, is connected to the water outlet 207. The container 203depicted in FIG. 3 comprises water. The part of the container thatcomprises water is called a water zone 217. The zone above the waterlevel is referred to as a steam zone 215. The water outlet 207 islocated in the water zone 217. The water outlet 207 is located at thelower half of a side wall of the container 203. The container 203further has a water inlet 211 to facilitate filling the container withwater. The inlet is provided with a pump 213. A hose 221 connects thepump 213 to a water tank 223. The water tank may be attached to a standcomprising the device 200 also referred to as boiler or steam generator.In many cases, the water tank 223 is removably arranged, so that a userof the device comprising the water tank is capable of bringing the watertank to a tap or the like in order to fill the water tank, withouthaving to move the entire device. The water may be pumped by the pump213 via the hose 221 under command of a pump signal from an electriccontrol device (not shown).

The heating element 205 heats the water in the container 203 to asuperheated state. The container is further provided with a steam outlet227 located in the steam zone 215. A second electro valve 229 is incommunication with the steam outlet 227. The second electro valve 229has an open and a closed position for allowing or preventing,respectively, steam generated inside the container to leave thecontainer. Typically the pressure in the container during use is in arange of 2-5 bar.

During generation of superheated water the first and second electrovalve 209, 229 are in closed position while the heating element heatsthe water. After the water reaches its superheated state, the firstelectro valve 209 may be triggered by the user or by a control unit (notshown) to its open position. As a result superheated water will be letout of the container 203 via the water outlet 207. The water will expandin an evaporation space outside the container 203 and thus steam isgenerated outside the container. The evaporation space in thisembodiment is a pipe. The pipe may have an increased radius tofacilitate evaporation of the superheated water. The pipe also functionsas a first transfer path 210 to transfer the steam generated by theexpanded superheated water to a place of use.

The steam generated inside the boiler 203 may leave the boiler 203 viathe steam outlet 227. The steam outlet 227 is in communication with asecond transfer path 230. In practice the second path 230 may be a tube,a pipe or a hose that allows for transfer of steam from the devicetoward a place where it may used.

Accordingly both transfer paths 210, 230 function to transport steam toa location where it can be advantageously applied, such as the soleplate of a steam iron.

It is important that the water outlet directly communicates with thewater zone, while the steam outlet directly communicates to the steamzone.

The first transfer path 210 and the second transfer 230 path are joinedvia a joining piece 240 to a mutual transfer path 242. This provides theflexibility of supplying steam generated inside the container, steamgenerated via evaporation of superheated water or a combination thereof.In case such a device is applied in combination with an iron steamgenerated inside the container and obtained via the steam outlet may beused for regular steam ironing whereas the steam generated byevaporation of superheated water may be used to give an additional shotof steam.

By combining the two steam paths into the mutual path no furthertechnical measures have to be taken from the side of the iron to handleboth steam sources. The iron may simply be connected to the mutualtransfer path to benefit from the invention.

Alternatively the mutual path 240 is absent and both transfer paths 210and 230 are individually connected to the iron. This way each transferpath may be used to provide steam at a different region in the soleplate. This provides flexibility in the design. For instance steamgenerated from superheated water may, via the first transfer path, betransferred to sole plate openings in a front zone located at the—socalled—tip of the iron. The steam obtained from the steam zone in thecontainer may, via the second transfer path, be transferred to soleplate openings in a back zone in the sole plate located closer to the—socalled—heel of the iron.

In FIG. 4 an embodiment of a domestic appliance according to theinvention is schematically depicted. The domestic appliance comprisesthe device 300 according to the invention and an iron 320. The deviceand iron are connected via a communication unit, also referred to astransfer path, 310 such as a hose or a tube.

The iron 320 has a body 322 and a soleplate 324 connected to the body.Usually, the body has the form of a housing having a handle andaccommodating several components of the iron. The soleplate comprises asteam chamber 330 having steam outlets 328, which outlets end up in thesole plate contact surface 326. A second heating element 332 having apower P2 is present in the soleplate for heating the steam chamber andthe sole plate surface.

The device 300 comprises a container 303 for containing water having aheating element 305 such as a heating plate, and a water outlet 307 forletting out superheated water. An electro valve 309 having an open and aclosed position, is connected to the water outlet 307. The water outlet307 is located at a side wall in the vicinity of the bottom of thecontainer 303. The container 303 may further have a water inlet (notshown) to facilitate filling the container with water. The containerdepicted in FIG. 4 comprises water. The part of the container thatcomprises water is called a water zone 317. The zone above the waterlevel is referred to as a steam zone 315. The water outlet 307 islocated in the water zone 317.

The heating element 305 heats the water in the container to asuperheated state. After the water reaches its superheated state, thefirst electro valve 309 may be triggered to its open position and as aresult superheated water will be let out of the container via the wateroutlet 307. The water will expand at an evaporation space 304 outsidethe container, a suitable location for the evaporation space isschematically indicated by nr 304. The steam generated via evaporationof superheated steam travels through the transfer path 310 to the iron320. The transfer path 310 is connected to the steam chamber 330 of theiron 320 via an iron transfer path 312. The steam reaches the steamoutlet opening 328 or openings provided in the sole plate of the ironvia the steam chamber 330. The steam chamber is typically heated by thesecond heating element 332 present in the sole plate 324, but anauxiliary heating element may instead be provided. The steam chamber mayfunction as evaporation space.

In practice when the electro valve 309 is triggered, it opens and steamtravels from the container 303, also referred to as boiler, to the iron320. Finally, the steam leaves the iron through the sole plate openings328. The construction from FIG. 3 having a first, a second, and a mutualtransfer path can also advantageously be applied in the domesticappliance shown in FIG. 4.

While the invention has been illustrated and described in detail in thedrawings and foregoing description, illustration and description are tobe considered illustrative or exemplary and not restrictive. Theinvention is not limited to the disclosed embodiments. Variations to thedisclosed embodiments can be understood and effected by the skilledperson in practicing the claimed invention, from a study of thedrawings, the description and the claims. The word “comprising” does notexclude other elements, and the indefinite article “a” or “an” does notexclude a plurality. Any reference sign in the Claims should not beconstrued as limiting the scope.

1. A device (1, 100, 200, 300) for supplying superheated water, comprising a container (3, 103, 203, 303) for containing water, a heating element (5, 105, 205, 305) for heating water in the container to a superheated state, and a water outlet (7, 107, 207, 307) for letting out superheated water.
 2. A device according to claim 1, wherein the container is provided with a water zone (17, 117, 217, 317) and a steam zone (15,115, 215, 315), the water outlet (7, 107, 207, 307) being located in the water zone.
 3. A device according to claim 1, wherein the water outlet is connected to an evaporation space (210) for evaporating superheated water.
 4. A device according to claim 1, wherein the device comprises a water inlet (11,211) for letting water into the container (3, 103, 203, 303), the water inlet being located in the steam zone (15,115, 215, 315).
 5. A device according to claim 1, wherein the water outlet comprises a valve (9, 109, 209, 309) having an open and a closed position.
 6. A device according to claim 1, wherein the device further comprises a steam outlet (227) located in the steam zone, the water outlet (7, 107, 207, 307) being in communication with a first transfer path (210, 310) and the steam outlet being in communication with a second transfer path (230).
 7. A device according to claim 6, wherein the first and second transfer path are joined to a mutual transfer path (242).
 8. A domestic appliance comprising a device (1, 100, 200, 300) according to claim
 1. 9. A domestic appliance according to claim 8, wherein the domestic appliance is a boiler ironing system further comprising an iron (320) having a sole plate opening (328) for letting out steam, the system having a communication unit (310) for transporting an output of superheated water from the water outlet (307) to the sole plate opening.
 10. A domestic appliance according to claim 9, wherein the domestic appliance is a garment care system further comprising a steamer having a steamer opening for letting out steam, the system having a communication unit for transporting an output of superheated water from the water outlet to the steamer opening.
 11. A method for generating steam using a device (1, 100, 200, 300) for supplying superheated water, comprising a container (3, 103, 203, 303) for containing water, a heating element (5, 105, 205, 305) for heating water in the container to a superheated state, and a water outlet (7, 107, 207, 307) for letting out superheated water wherein the water outlet comprises a valve (9, 109, 209, 309) having an open and a closed position, the method comprising the steps of providing a water level in the container such that the water outlet is at least partially below the water level and heating water to a superheated state, after that using the valve in the open position 